I currently have a Zalman 9700. It's not bad but as others have pointed out it isn't that great compared to Thermalright's IFX or Ultra Extreme. The problem is the tests I've seen have been only on C2D not on Quads.

What I've seen reference to is that the heavy Thermalright products weigh down on some of the cores thus giving a heat disparity between them...sometimes as great as 15C. For example by simply lifting the weight of the Ultra off of the board with you hand will equalize the temp.

Therefore, even though the cooling of these Ultras are almost as good as water on C2D, I wonder if water is the only solution so that the heat dispensation is equal on all cores?